The Constitution of the Republic of South Africa, 1996 (Act 108 of 1996) stipulates that every person has the right of access to information held by government. To give effect to this right, legislation in the form of the Promotion of Access to Information Act, 2000 (Act 2 of 2000) was promulgated. This study explores the access to information regime that was established by die aforementioned legislation with specific reference to similar regimes in the United States of America, Australia, New Zealand and Canada. Attention is also devoted to the prerequisites and potential obstacles associated with the implementation of the Promotion of Access to Information Act, 2000. Based on the practices in other states, the conclusion was reached that the nature of information that may be requested in the South African context should be expanded, that cabinet records should only be excluded to the extent that disclosure thereof would be harmful, that frequently requested records should be made automatically available and that decision-making guidelines of government institutions should be published. As far as procedural requirements are concerned, it is proposed that information officers should acknowledge receipt of requests and that, where necessary, records should be translated to ensure that they are useful to a requester. It is further proposed that the wording of the ground of refusal regarding policy formulation and decision-making in government institutions be amended to take account of the consequences of disclosure. It is imperative that appeal and review mechanisms be accessible to members of the public and it is therefore proposed that an information commissioner be instituted to settle disputes in information related matters. Lastly it is proposed that sanctions be imposed against officials who deliberately undermine the public's right of access to information and that separate units be established in government institutions to deal exclusively with requests for access to information. / Public Administration / D. Litt. et Phil. (Public Administration)

The application of information communication technologies (ICTs) in records management in many organisations underscores the need for the assessment of e-records readiness. This provides a useful guide in benchmarking, gauging progress and comprehending e-records management. This study examined e-record readiness in labour organisations with a view to proposing a framework for labour organisations in Botswana. The study was largely guided by a quantitative paradigm and used a survey research strategy. This was complemented by methodological triangulation of both quantitative and qualitative data collection methods. All the 50 registered labour organisations in Botswana were surveyed, 45 of which responded, representing a response rate of 90%. Data was obtained through structured questionnaires, semi-structured interviews, document review and observations. The study established that e-records readiness in labour organisations in Botswana was evident, low and evolving, evidenced by the slow adoption of ICTs; inadequate records management standards and practices; and low integration in the national e-readiness framework. The study confirmed that most labour organisations had embraced the utilisation of ICTs in their work; exhibited some form of records management function and acknowledged the existence of national policy directives and strategies on e-readiness. However, traditional ICTs mainly the fax and telephone, were more prevalently adopted and used than newer ones such as e-mail and the Internet. The use of social media technology (Web 2.0 - Facebook, YouTube, and Twitter) was yet to be explored. The management of both paper-based and electronic records was not satisfactory and fell short of best recognised records management standards and practice. The integration of labour organisations into national e-readiness initiatives as espoused in key policy proclamations within the context of the pursuance of a holistic knowledge and information society was slow and remained challenging. In order to foster successful e-records readiness in labour organisations, several recommendations were advanced that underscored effective ICT adoption and use, implementation of best records management practices and rigorous integration of labour organisations into the information and knowledge society in Botswana. In addition, an integrated framework for examining and understanding e-records readiness in labour organisations was proposed and documented. / Information Science / D. Litt. et Phil. (Information Science)

"A distributed queueing Medium Access Control (MAC) protocol is used in Distributed Queue Dual Bus (DQDB) networks. A modified version of the MAC protocol was proposed by R.R. Pillai and U. Mukherji in an attempt to overcome some of the shortcomings of the DQDB MAC protocol. They analyzed the performance of the system for Bernoulli arrivals and for large propagation delays between the nodes. We extend the performance analysis of the modified MAC protocol for a DQDB type of Network. The parameter of interest to us is the bus access delay. This has two components, viz., the request bus access delay and the data bu6 access delay. We use the model at the request point at node and present methods to evaluate the delay experienced in such a model. The model is an n-priority ./D/l queue with D vacations (non-preemptive priority) where n is the number of nodes sending requests on the request bus for transmission on the data bus. The methods presented help to evaluate the request bus access delay when the arrivals at each node are Markovian Arrival Processes (MAPs). The algorithms for evaluating the mean request bus access delay are based on matrix geometric techniques. Thus, one can use the algorithms developed in the literature to solve for the finite buffers case too. This model, for the request bus access delay, holds irrespective of the propagation delay between the nodes. We also evaluate the inter-departure time of class 1 customers and virtual customers in a 2-priority M/G/l system with G vacations (non-preemptive priority). In the case of Poisson arrivals at all the nodes, we would have a 2-priority M/D/l system with D vacations (non-preemptive priority). We thus evaluate the inter-arrival time of the free slots on the data bus as seen by Node 2. Note that this is independent of the number of active nodes in the network We then develop methods to evaluate the mean data bus access delay experienced by the customers at Node 2 in a three-node network with 2 nodes communicating with the third when the propagation delay between the nodes is large. We consider the case of finite Local Queue buffers at the two nodes. Using this assumption we arrive at process of arrivals to the Combined Queue and the process of free slots on the data bus to be Markov Modulated Bernoulli processes. The model at the combined queue at Node 2 then has a Quasi Birth-Death evolution. Thus, this system is solved by using the Ramaswami-Latouche algorithm. The stationary probabilities are then used to evaluate the mean data bus access delay experienced at Node 2. The finite buffer case of this system can be solved by G.Wi Stewart's algorithm. The method in modelling the system and the results are presented in detail for Poisson arrivals. The extension of this to more complex processes is also explained. We encounter in the analysis an explosion of the state-space of the system. We try to counter this by considering approximations to the process of free slots on the data bus. The approximations considered are on the basis of what are known as Idealized Aggregates. The performance of the approximation is also detailed. It works very well under low and moderate load but underestimates the mean delay under heavy load. Thereafter, we discuss the performance of the system with reference to the mean of the access delay and the standard deviation of the access delay under varying traffic at the two nodes. For this part we use simulation results to discuss the performance. The comparison between the performance measures at both the nodes is also done. Then we develop methods/techniques to understand the performance of the system when we have finite propagation delays between the nodes. We concentrate on the 3-node problem and calculate performance bounds based on linear programs. This is illustrated in detail for Bernoulli arrivals for the case of 1 slot propagation delay between the nodes as well as for the case of 2 slots propagation delay. The performance of the bounds obtained is also detailed. The presence of an idling system at the combined queue of Node 2 makes the bounds somewhat loose. Finally, we discuss the performance of the system with reference to the mean access delay and the standard deviation of the access delay under varying load on the system. Again, we rely on simulation studies. Finally, we study the performance of the system as a multiplexer. For this, we re­strict the traffic to Markov Modulated Processes (or those which would satisfy the Gartner-Ellis Theorem requirements). The traffic is characterized by what are known as Envelope Processes - Lower and Upper. The class of processes which satisfy the conditions of the Gartner-Ellis theorem come under the category where both the Envelope Processes exist and the Minimum Envelope Rate and the Maximum Lower Envelope Rate are the same. We use the system evolution equations at the combined queue at any node to develop re­lations between the various input and output processes. First, this is done for a. system of this kind, in isolation. Then, we consider this system as a part of the modified protocol and present relations, among the various input and output processes, which are specific to the modified protocol. The possible use of all of the above to do Admission Control at the entry point to the Asynchronous Transfer Mode (ATM) network is also presented.

The Electric/Electronic architecture of vehicle becomes more complex and costly, self-adaption can reduce the system, enhance the adaptive meanwhile reduce energy consumption and costs. The self-adaption needs the cooperation of both hardware and software reconfigurations, such that after the software is reconfigured the automotive network continues to fulfill the time constraints for time-critical applications. The thesis focuses on the real-time network reconfiguration. It uses EAST-ADL to model a real-time automotive system with timing events and constraints, which conforms to AUTOSAR timing extensions. The network media access is analyzed based on the model and a scheduling algorithm is developed. Then the concept is implemented by a use case, which is transformed from an EAST-ADL model to an executable simulation.

No description available.

Retail stores rely on consumers to maintain their businesses and growth. Much of their success depends on the safety and security of consumers. The more people come and buy the products, the more profitable the stores become. If the safety and security of consumers (or their perceptions thereof) at a shopping centre where a retail store is sited is in question, consumers may well stop frequenting such centres and do their shopping at other retail centres at which they perceive to be more safe and secure to do their shopping. Consumers’ ‘peace-of-mind’ plays a vital role in their selection of which retail store(s) to frequent and will often determine whether a repeat visit will occur. The extent of incidents of crime of whatever nature at a particular shopping centre will also impact negatively on shoppers’ perceptions of ‘how safe it is to shop’ at particular centres. Security measures differ from one retail store to another and also between the size and layout, as well as the location of the retail store. The rate at which criminal offences take place at retail stores is currently vague or unknown. Therefore, it is vital that specific risks confronting these retail stores should be identified and analysed with the intention of recommending specific security measures. Business crime and violence present significant threats to consumers’ safety and security in South Africa. High levels of business associated crimes have compelled communities and business bodies such as retail stores to provide their own security for the protection of their assets, as well as consumers. Effective security measures are a prerequisite at retail stores to ensure the safety and security of consumers whilst visiting retail stores. Precaution ought to be taken when dealing with any crime problem that affects consumers at any business environment, in this study more precisely: retail stores. The study explored the existing security measures at retail stores for the protection of consumers. The researcher employed qualitative methods: one-on-one interviews with participants and site observations at selected retail stores. There were 30 participants (20 consumers and 10 security officers). The study found the following:  Retail stores were exposed to security risks such as theft; shoplifting; common robbery; armed robbery; fraud; arson and assaults (grievous bodily harm) and burglary.  The security measures that are currently in place are not adequate to protect retail stores. These security measures differ from one retail store to the next.  In order to improve safety and security at retail stores there should be a security standard that is applicable to the retail stores. Based on the findings, some of the recommendations were as follows:  Retail stores should be protected in line with the level of risk of the area where the retail store is situated: low risk; medium risk; and high risk.  Security managers should conduct security awareness regularly.  Threat assessments should be conducted regularly as well.  Consumers are encouraged to report to the Security manager at the retail store any suspicious actions; persons; objects; and vehicles. / Criminology and Security Science / M. Tech. (Security Management)

The Constitution of the Republic of South Africa, 1996 (Act 108 of 1996) stipulates that every person has the right of access to information held by government. To give effect to this right, legislation in the form of the Promotion of Access to Information Act, 2000 (Act 2 of 2000) was promulgated. This study explores the access to information regime that was established by die aforementioned legislation with specific reference to similar regimes in the United States of America, Australia, New Zealand and Canada. Attention is also devoted to the prerequisites and potential obstacles associated with the implementation of the Promotion of Access to Information Act, 2000. Based on the practices in other states, the conclusion was reached that the nature of information that may be requested in the South African context should be expanded, that cabinet records should only be excluded to the extent that disclosure thereof would be harmful, that frequently requested records should be made automatically available and that decision-making guidelines of government institutions should be published. As far as procedural requirements are concerned, it is proposed that information officers should acknowledge receipt of requests and that, where necessary, records should be translated to ensure that they are useful to a requester. It is further proposed that the wording of the ground of refusal regarding policy formulation and decision-making in government institutions be amended to take account of the consequences of disclosure. It is imperative that appeal and review mechanisms be accessible to members of the public and it is therefore proposed that an information commissioner be instituted to settle disputes in information related matters. Lastly it is proposed that sanctions be imposed against officials who deliberately undermine the public's right of access to information and that separate units be established in government institutions to deal exclusively with requests for access to information. / Public Administration and Management / D. Litt. et Phil. (Public Administration)

The application of information communication technologies (ICTs) in records management in many organisations underscores the need for the assessment of e-records readiness. This provides a useful guide in benchmarking, gauging progress and comprehending e-records management. This study examined e-record readiness in labour organisations with a view to proposing a framework for labour organisations in Botswana. The study was largely guided by a quantitative paradigm and used a survey research strategy. This was complemented by methodological triangulation of both quantitative and qualitative data collection methods. All the 50 registered labour organisations in Botswana were surveyed, 45 of which responded, representing a response rate of 90%. Data was obtained through structured questionnaires, semi-structured interviews, document review and observations. The study established that e-records readiness in labour organisations in Botswana was evident, low and evolving, evidenced by the slow adoption of ICTs; inadequate records management standards and practices; and low integration in the national e-readiness framework. The study confirmed that most labour organisations had embraced the utilisation of ICTs in their work; exhibited some form of records management function and acknowledged the existence of national policy directives and strategies on e-readiness. However, traditional ICTs mainly the fax and telephone, were more prevalently adopted and used than newer ones such as e-mail and the Internet. The use of social media technology (Web 2.0 - Facebook, YouTube, and Twitter) was yet to be explored. The management of both paper-based and electronic records was not satisfactory and fell short of best recognised records management standards and practice. The integration of labour organisations into national e-readiness initiatives as espoused in key policy proclamations within the context of the pursuance of a holistic knowledge and information society was slow and remained challenging. In order to foster successful e-records readiness in labour organisations, several recommendations were advanced that underscored effective ICT adoption and use, implementation of best records management practices and rigorous integration of labour organisations into the information and knowledge society in Botswana. In addition, an integrated framework for examining and understanding e-records readiness in labour organisations was proposed and documented. / Information Science / D. Litt. et Phil. (Information Science)

L'objectif de la thèse est d'étudier la variation temporelle de la qualité des liens dans les réseaux de capteurs sans fil à grande échelle, de concevoir des estimateurs permettant la différenciation, à court terme et long terme, entre liens de qualité hétérogène. Tout d'abord, nous étudions les caractéristiques de deux paramètres de la couche physique: RSSI (l'indicateur de puissance du signal reçu) et LQI (l'indicateur de la qualité de liaison) sur SensLab, une plateforme expérimentale de réseau de capteurs à grande échelle situé à l'intérieur de bâtiments. Nous observons que le RSSI et le LQI permettent de discriminer des liens de différentes qualités. Ensuite, pour obtenir un estimateur de PRR, nous avons approximé le diagramme de dispersion de la moyenne et de l'écart-type du LQI et RSSI par une fonction Fermi-Dirac. La fonction nous permet de trouver le PRR à partir d'un niveau donné de LQI. Nous avons évalué l'estimateur en calculant le PRR sur des fenêtres de tailles variables et en le comparant aux valeurs obtenues avec l'estimateur. Par ailleurs, nous montrons en utilisant le modèle de Gilbert-Elliot (chaîne de Markov à deux états) que la corrélation des pertes de paquets dépend de la catégorie de lien. Le modèle permet de distinguer avec précision les différentes qualités des liens, en se basant sur les probabilités de transition dérivées de la moyenne et de l'écart-type du LQI. Enfin, nous proposons un modèle de routage basé sur la qualité de lien déduite de la fonction de Fermi-Dirac approximant le PRR et du modèle Markov Gilbert-Elliot à deux états. Notre modèle est capable de distinguer avec précision les différentes catégories de liens ainsi que les liens fortement variables. / The goal of the thesis is to investigate the issues related to the temporal link quality variation in large scale WSN environments, to design energy efficient link quality estimators able to distinguish among links with different quality on a short and a long term. First, we investigate the characteristics of two physical layer metrics: RSSI (Received Signal Strength Indication) and LQI (Link Quality Indication) on SensLAB, an indoor large scale wireless sensor network testbed. We observe that RSSI and LQI have distinct values that can discriminate the quality of links. Second, to obtain an estimator of PRR, we have fitted a Fermi-Dirac function to the scatter diagram of the average and standard variation of LQI and RSSI. The function enables us to find PRR for a given level of LQI. We evaluate the estimator by computing PRR over a varying size window of transmissions and comparing with the estimator. Furthermore, we show using the Gilbert-Elliot two-state Markov model that the correlation of packet losses and successful receptions depend on the link category. The model allows to accurately distinguish among strongly varying intermediate links based on transition probabilities derived from the average and the standard variation of LQI. Finally, we propose a link quality routing model driven from the F-D fitting functions and the Markov model able to discriminate accurately link categories as well as high variable links.

A wireless sensor network (WSN) is a collection of sensor nodes distributed over a geographical region to obtain the environmental data. It can have different types of applications ranging from low data rate event driven and monitoring applications to high data rate real time industry and military applications. Energy efficiency and reliability are the two major design issues which should be handled efficiently at all the layers of communication protocol stack, due to resource constraint sensor nodes and erroneous nature of wireless channel respectively. Media access control (MAC) is the protocol which deals with the problem of packet collision due to simultaneous transmissions by more than one neighboring sensor nodes. Time Division Multiple Access based (TDMA-based) and contention-based are the two major types of MAC protocols used in WSNs. In general, the TDMA-based channel access mechanisms perform better than the contention-based channel access mechanisms, in terms of channel utilization, reliability and power consumption, specially for high data rate applications in wireless sensor networks (WSNs). TDMA-based channel access employs a predefined schedule so that the nodes can transmit at their allotted time slots. Based on the frequency of scheduling requirement, the existing distributed TDMA-scheduling techniques can be classified as either static or dynamic. The primary purpose of static TDMA-scheduling algorithms is to improve the channel utilization by generating a schedule of smaller length. But, they usually take longer time to generate such a schedule, and hence, are not suitable for WSNs, in which the network topology changes dynamically. On the other hand, dynamic TDMA-scheduling algorithms generate a schedule quickly, but they are not efficient in terms of generated schedule length. We suggest a new approach to TDMA-scheduling for WSNs, that can bridge the gap between these two extreme types of TDMA-scheduling techniques, by providing the flexibility to trade-off between the schedule length and the time required to generate the schedule, as per the requirements of the underlying applications and channel conditions. The suggested TDMA-scheduling works in two phases. In the first phase, we generate a valid TDMA schedule quickly, which need not have to be very efficient in terms of schedule length. In the second phase, we iteratively reduce the schedule length in a manner, such that the process of schedule length reduction can be terminated after the execution of an arbitrary number of iterations, and still be left with a valid schedule. This step provides the flexibility to trade-off the schedule length with the time required to generate the schedule. In the first phase of above TDMA-scheduling approach, we propose two randomized, distributed and parallel TDMA-scheduling algorithms viz., Distributed TDMA Slot Scheduling (DTSS) and Randomized and Distributed TDMA (RD-TDMA) scheduling algorithm. Both the algorithms are based on graph coloring approach, which generate a TDMA schedule quickly with a fixed schedule length ( Colouring), where is the maximum degree of any node in the graph to be colored. The two algorithms differ in the channel access mechanism used by them to transmit control messages, and in the generated schedule for different modes of communication, i.e., unicast, multicast and broadcast. The novelty of the proposed algorithms lies in the methods, by which an uncolored node detects that the slot picked by it is different from the slots picked by all the neighboring nodes, and the selection of probabilities with which the available slots can be picked up. Furthermore, to achieve faster convergence we introduce the idea of dynamic slot-probability update as per which the nodes update their slot-probability by considering the current slot-probability of their neighboring nodes. Under the second phase of the proposed TDMA-scheduling approach, we provide two randomized and distributed schedule compaction algorithms, viz., Distributed Schedule Compaction (DSC) and Distributed Schedule Length Reduction (DSLR) algorithm, as the mechanism to trade-off the scheduling time with the generated schedule length. These algorithms start with a valid TDMA schedule and progressively compress it in each round of execution. Additionally, Furthermore, the execution of these algorithms can be stopped after an arbitrary number of rounds as per the requirements of underlying applications. Even though TDMA-based MAC protocols avoid packet loss due to collision, due to erroneous nature of wireless medium, they alone are not sufficient to ensure the reliable transmission in WSNs. Automatic Repeat reQuest (ARQ) is the technique commonly used to provide error control for unicast data transmission. Unfortunately, ARQ mechanisms cannot be used for reliable multicast/broadcast transmission in WSNs. To solve this issue, we propose a virtual token-based channel access and feedback protocol (VTCAF) for link level reliable multicasting in single-hop wireless networks. The VTCAF protocol introduces a virtual (implicit) token passing mechanism based on carrier sensing to avoid the collision between feedback messages. The delay performance is improved in VTCAF protocol by reducing the number of feedback messages. Besides, the VTCAF protocol is parametric in nature and can easily trade-off reliability with the delay as per the requirements of the underlying applications. Finally, by integrating all the works, viz., TDMA-scheduling algorithms (DTSS/RD-TDMA), schedule compaction algorithms and link layer feedback mechanism for reliable multicast/ broadcast, we propose a TDMA-based energy aware and reliable MAC protocol, named TEA-MAC for multi-hop WSNs. Similar to VTCAF, TEA-MAC protocol uses the combination of ACK-based and NACK-based approaches to ensure reliable communication. But, instead of using virtual token-based channel access, it uses contention-based channel access for NACK transmission. All the algorithms and protocols proposed in this thesis are distributed, parallel and fault tolerant against packet losses to support scalability, faster execution and robustness respectively. The simulations have been performed using Castalia network simulator to evaluate the performance of proposed algorithms/protocols and also to compare their performance with the existing algorithms/protocols. We have also performed theoretical analysis of these algorithms/protocols to evaluate their performance. Additionally, we have shown the correctness of proposed algorithms/protocols by providing the necessary proofs, whenever it was required. The simulation results together with theoretical analysis show that, in addition to the advantage of trading the runtime with schedule length, the proposed TDMA scheduling approach achieves better runtime and schedule length performance than existing algorithms. Additionally, the TEA-MAC protocol is able to considerably improve the reliability and delay performance of multicast communication in WSNs.